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The present invention relates to aerosol air fresheners, and more particularly to apparatus for automatically dispensing an air freshening substance at controlled intervals.
Air fresheners are commonly used to mask odors within bathrooms and other interior spaces. The air freshening substance may also chemically neutralize the odors. Devices have been developed to automatically dispense the air freshening substance.
One common type of dispenser utilizes a scented liquid contained in a pressurized canister. The canister is mounted in a holder which includes a motor that periodically operates a valve on the canister to dispense the scented liquid into the environment. The motor is periodically activated by a timer. The timing period typically is fixed and cannot be varied to meet the needs of a particular room in which the dispenser is installed. As a consequence, a greater amount of scented liquid may be dispensed into a room with a mild odor problem, and an insufficient amount of the scented liquid may be dispensed in a room with more persistent odors.
Furthermore, once installed and activated, the device dispenses the scented liquid at regular intervals until the air freshener becomes depleted. Thus if the room is not occupied for a long period of time, during which air freshening is not required, the scented liquid continues to be dispensed at the same rate as when the room is occupied. It is desirable to control the dispensing in relation to the occupancy or usage of the room in which the dispenser is located.
It is also desirable to provide a mechanism which indicates to the user when the supply of scented liquid in the canister becomes depleted. Otherwise the user has to periodically open the dispenser housing and inspect the canister to determine depletion of the air freshening substance therein.
An apparatus periodically discharges a quantity of the contents of a canister, for example an air freshening substance, into a room. The apparatus has a motor which drives a member that engages the canister to open a valve thereby allowing the contents of the canister to be discharged.
A sensor responds to a characteristic of the room and produces a signal indicating that characteristic. The characteristic provides an indication of occupancy or usage of the room. In the preferred embodiment of the present apparatus, the sensor detects the magnitude of light within the room.
A control circuit is connected to the sensor and the motor. An input device is provided which enables a user to designate a dispense interval specifying the frequency at which the contents of the canister are to be discharged into a room. The control circuit evaluates the signal from the sensor to determine whether the room is being used. For example if the magnitude of light within the room exceeds a threshold level, as occurs when the room lighting is on, a controller determines that the room is in use and occupied. The controller periodically activates the motor at intervals which correspond to the selected dispense interval when a determination is made that the room is being used, and at other times the controller periodically activates the motor at intervals which are longer than the dispense interval.
Thus the contents of the canister are dispensed more frequently when the room is in use, than when it is unoccupied. Therefore, the contents of the canister are conserved for periods of room usage while still providing a degree of dispensing at other times.